This invention relates to the separation of liquid mixtures without subjecting the mixture to thermal distillation.
Thermal distillation is widely used for separating miscible liquid components with different boiling points. Thermal distillation technology is well developed and is used widely. For example, one of the huge market-driven thermal distillation applications is ethanol production, wherein alcohol is separated from a fermentation mixture by fractional distillation. Although the net energy produced in this process is low, thermal fractional distillation is the widely accepted separation method. Less common known ways of separating miscible liquid mixtures are vacuum distillation, electric field separation, and membrane separation.
Ultrasonic atomization processes have been explored for separating water and ethanol in laboratory-scale bench top experiments. Research has shown that an atomized mist becomes richer in ethanol with time as compared to the mixture of ethanol and water they started with. However, there is no prior art scalable process technology for a miscible liquid separation based on ultrasonic atomization, without using thermal distillation. The scaling issues in ultrasonic methods are extremely complex. Some of the well-recognized scaling problems come from the heating effect of ultrasonic transducers, the liquid mixing, and liquid extraction, maintaining a constant liquid level above the atomizer surface, and mist composition (liquid mass mist loading in air). As a result, prior art in ultrasonic separation is absent at the commercial scale and throughput is limited.
Typical ethanol production by thermal distillation is given here as an example. Fermentation is used to produce alcoholic beverages. Beer and wine do not contain more than around 12% alcohol, because a higher concentration kills the yeast that produce the alcohol. To make stronger drink, fractional distillation is used. Wine, beer, or fermented brews made from corn, sugar cane potatoes or other starches can be made richer in alcohol by distillation. Since ethyl alcohol boils at only 78° C., while water boils at 100° C., the alcohol will boil off, leaving the water behind. The alcohol vapors are then condensed and collected. Distillation can produce liquors that range from 40-95% ethyl alcohol. The energy for distillation based on the latent heat of vaporization of ethanol is 884 kJ/kg, without considering the heat transfer limitations (efficiency factor <1.0) in distillation. A need exists to reduce the energy required in production of ethanol and separation of liquid mixtures.